A Cell-Mimicking Structure Converting Analog Volume Changes to Digital Colorimetric Output with Molecular Selectivity

Area of Science:

• Biomimetic materials science
• Nanotechnology
• Supramolecular chemistry

Background:

• Artificial cell design is crucial for understanding life's origins and developing advanced functional materials.
• Existing protocell models often lack the complexity and integrated functions of natural cells.

Purpose of the Study:

• To create a three-component, cell-mimicking structure with integrated functionalities.
• To demonstrate a responsive material system that translates analog stimuli into digital outputs.
• To provide a modular platform for designing novel functional materials.

Main Methods:

• Fabrication of a tripartite structure: iron oxide nanozyme core, molecularly imprinted hydrogel shell, and lipid bilayer membrane.
• Characterization using cryo-transmission electron microscopy (TEM), negative stain TEM, and calcein leakage assay.
• Investigation of salt concentration-dependent swelling/shrinking of the hydrogel shell and its effect on membrane integrity and substrate oxidation (TMB).
• Incorporation of melittin for controlled membrane permeability and molecular imprinting for selective transport.

Main Results:

• Successful construction and characterization of the cell-mimicking structure.
• Demonstration of salt concentration-induced hydrogel volume changes leading to membrane rupture and a switch-like colorimetric response.
• Achieved controlled molecular transport through melittin channels and the imprinted hydrogel.
• Coupled functions of the nanozyme, hydrogel, and membrane were confirmed.

Conclusions:

• The developed tripartite structure effectively mimics cellular components and functions.
• This system offers a novel approach for creating responsive materials with tunable outputs.
• The modular design provides a versatile platform for advanced material development and protocell research.